CuX<sub>2</sub>-Mediated Halolactonization Reaction of Monoesters of 1,2-Allenyl Phosphonic Acids and Their Suzuki Cross-Coupling Reaction
作者:Fei Yu、Xiongdong Lian、Jinbo Zhao、Yihua Yu、Shengming Ma
DOI:10.1021/jo802051r
日期:2009.2.6
(X = Cl, Br) halolactonization of monoesters of 1,2-allenyl phosphonicacids is presented. The reaction proceeded smoothly under the mild condition for differently substituted allenic substrates giving the 4-halo-2,5-dihydro[1,2]oxaphosphole 2-oxides in good yields. The Suzuki cross-coupling reaction of these bromides and even chlorides with organic boronic acids under the catalysis of PdCl2(Sphos)2
Dehydrative Cp*Co(III)-Catalyzed C–H Bond Allenylation
作者:Malay Sen、Pardeep Dahiya、J. Richard Premkumar、Basker Sundararaju
DOI:10.1021/acs.orglett.7b01415
日期:2017.7.21
unprecedented reactivity of Cp*Co(III) for the synthesis of tetrasubstituted allenes under mild conditions is disclosed. Electron-rich and highly nucleophilic cobalt facilitates the dehydrative C–H bond allenylation directly from propargylic alcohols without any derivatization. The reaction proceeds via reversible cyclometalation followed by alcohol-directed regioselective alkyne insertion and β-hydroxy elimination